Sensor-based shape identification

ABSTRACT

A controller for determining shape of an interventional device includes a memory that stores instructions, and a processor that executes the instructions. When executed by the processor, the instructions cause the controller to execute a process that includes controlling an imaging probe to emit at least one tracking beam to an interventional medical device over a period of time comprising multiple different points of time. The process also includes determining a shape of the interventional medical device, based on a response to the tracking beams received over the period of time from a first sensor that moves along the interventional medical device during the period of time relative to a fixed location on the interventional medical device for the period of time.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This application is the U.S. National Phase application under 35 U.S.C.§ 371 of International Application No. PCT/EP2019/053929, filed on Feb.18, 2019, which claims the benefit of U.S. Provisional PatentApplication No. 62/633,826, filed on Feb. 22, 2018. These applicationsare hereby incorporated by reference herein.

BACKGROUND

InSitu technology estimates position of a passive ultrasound sensor inthe field of view of a known diagnostic B-mode ultrasound image byanalyzing the signal received by the passive ultrasound sensor as thebeams of the ultrasound imaging probe sweep the insonified field.Time-of-flight measurements provide the axial/radial distance of thepassive ultrasound sensor from the imaging array, while amplitudemeasurements and knowledge of the beam firing sequence provide thelateral/angular position of the passive ultrasound sensor.

FIG. 1 illustrates a known system for tracking an interventional medicaldevice using a passive ultrasound sensor. In FIG. 1 , an ultrasoundprobe 102 emits an imaging beam 103 that sweeps across a passiveultrasound sensor 104 on a tool tip of an interventional medical device105. An image of tissue 107 is fed back by the ultrasound probe 102. Alocation of the passive ultrasound sensor 104 on the tool tip of theinterventional medical device 105 is provided as a tip location 108 upondetermination by a signal processing algorithm. The tip location 108 isoverlaid on the image of tissue 107 as an overlay image 109. The imageof tissue 107, the tip location 108, and the overlay image 109 are alldisplayed on a display 100.

SUMMARY

According to an aspect of the present disclosure, a controller fordetermining shape and/or path of an interventional device includes amemory that stores instructions, and a processor that executes theinstructions. When executed by the processor, the instructions cause thecontroller to execute a process that includes controlling an imagingprobe to emit at least one tracking beam to an interventional medicaldevice over a period of time comprising multiple different points oftime. The process also includes determining a shape and/or path of theinterventional medical device, based on a response to the tracking beamsreceived over the period of time from a first sensor that moves alongthe interventional medical device during the period of time relative toa fixed location on the interventional medical device for the period oftime.

According to another aspect of the present disclosure, a method fordetermining shape and/or path of an interventional device includescontrolling, by a processor that executes instructions stored in amemory, an imaging probe to emit at least one tracking beam to aninterventional medical device over a period of time comprising multipledifferent points of time. The method also includes determining a shapeand/or path of the interventional medical device, based on a response tothe tracking beams received over the period of time from a first sensorthat moves along the interventional medical device during the period oftime relative to a fixed location on the interventional medical devicefor the period of time.

According to yet another aspect of the present disclosure, a controllerfor determining shape and/or path of an interventional device includes amemory that stores instructions, and a processor that executes theinstructions. When executed by the processor, the instructions cause thecontroller to execute a process that includes controlling an imagingprobe to emit at least one tracking beam to an interventional medicaldevice over a period of time comprising multiple different points oftime. The process executed by the controller also includes determining ashape and/or path of the interventional medical device, based on aresponse to the tracking beams received over the period of time from afirst sensor fixed on the interventional medical device during theperiod of time relative to a fixed location on the interventionalmedical device during the period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

The example embodiments are best understood from the following detaileddescription when read with the accompanying drawing figures. It isemphasized that the various features are not necessarily drawn to scale.In fact, the dimensions may be arbitrarily increased or decreased forclarity of discussion. Wherever applicable and practical, like referencenumerals refer to like elements.

FIG. 1 illustrates a known system for interventional medical devicetracking using a passive ultrasound sensor, in accordance with arepresentative embodiment.

FIG. 2A illustrates an ultrasound system for sensor-based shapeidentification, in accordance with a representative embodiment.

FIG. 2B illustrates another ultrasound system for sensor-based shapeidentification, in accordance with a representative embodiment.

FIG. 2C is an illustrative embodiment of a general computer system, onwhich a method of sensor-based shape identification can be implemented,in accordance with a representative embodiment.

FIG. 3 illustrates an interventional medical device used forsensor-based shape identification, in accordance with a representativeembodiment.

FIG. 4A illustrates another interventional medical device used forsensor-based shape identification, in accordance with a representativeembodiment.

FIG. 4B illustrates operation of the interventional medical device usedfor sensor-based shape identification in FIG. 4A, in accordance with arepresentative embodiment.

FIG. 4C illustrates the operation of the interventional medical deviceused for sensor-based shape identification in FIG. 4A, in accordancewith a representative embodiment.

FIG. 4D illustrates another operation of the interventional medicaldevice used for sensor-based shape identification in FIG. 4A, inaccordance with a representative embodiment.

FIG. 5 illustrates a process for sensor-based shape identification, inaccordance with a representative embodiment.

FIG. 6 illustrates another process for sensor-based shapeidentification, in accordance with a representative embodiment.

FIG. 7 illustrates a sequence in which fixed sensor can be used toisolate probe motion for sensor-based shape identification, inaccordance with a representative embodiment.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation andnot limitation, representative embodiments disclosing specific detailsare set forth in order to provide a thorough understanding of anembodiment according to the present teachings. Descriptions of knownsystems, devices, materials, methods of operation and methods ofmanufacture may be omitted so as to avoid obscuring the description ofthe representative embodiments. Nonetheless, systems, devices, materialsand methods that are within the purview of one of ordinary skill in theart are within the scope of the present teachings and may be used inaccordance with the representative embodiments. It is to be understoodthat the terminology used herein is for purposes of describingparticular embodiments only, and is not intended to be limiting. Thedefined terms are in addition to the technical and scientific meaningsof the defined terms as commonly understood and accepted in thetechnical field of the present teachings.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements or components, theseelements or components should not be limited by these terms. These termsare only used to distinguish one element or component from anotherelement or component. Thus, a first element or component discussed belowcould be termed a second element or component without departing from theteachings of the inventive concept.

The terminology used herein is for purposes of describing particularembodiments only, and is not intended to be limiting. As used in thespecification and appended claims, the singular forms of terms ‘a’, ‘an’and ‘the’ are intended to include both singular and plural forms, unlessthe context clearly dictates otherwise. Additionally, the terms“comprises”, and/or “comprising,” and/or similar terms when used in thisspecification, specify the presence of stated features, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, elements, components, and/or groups thereof. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items.

Unless otherwise noted, when an element or component is said to be“connected to”, “coupled to”, or “adjacent to” another element orcomponent, it will be understood that the element or component can bedirectly connected or coupled to the other element or component, orintervening elements or components may be present. That is, these andsimilar terms encompass cases where one or more intermediate elements orcomponents may be employed to connect two elements or components.However, when an element or component is said to be “directly connected”to another element or component, this encompasses only cases where thetwo elements or components are connected to each other without anyintermediate or intervening elements or components.

In view of the foregoing, the present disclosure, through one or more ofits various aspects, embodiments and/or specific features orsub-components, is thus intended to bring out one or more of theadvantages as specifically noted below. For purposes of explanation andnot limitation, example embodiments disclosing specific details are setforth in order to provide a thorough understanding of an embodimentaccording to the present teachings. However, other embodimentsconsistent with the present disclosure that depart from specific detailsdisclosed herein remain within the scope of the appended claims.Moreover, descriptions of well-known apparatuses and methods may beomitted so as to not obscure the description of the example embodiments.Such methods and apparatuses are within the scope of the presentdisclosure.

As described herein, shape of a wire or device can be identified usingone or more passive ultrasound sensors such as an InSitu sensor. Inembodiments, a first passive ultrasound sensor is movable along a firstdevice relative to a fixed location, and the movable sensor and fixedlocation are used to identify the shape of the wire or device. Inembodiments, a second passive ultrasound sensor at the fixed locationserves as a fixed reference marker, for example to compensate for tissueand/or probe motion.

FIG. 2A illustrates an ultrasound system for sensor-based shapeidentification, in accordance with a representative embodiment.

In FIG. 2A, an ultrasound system 200 includes a central station 250 witha processor 251 and memory 252, a touch panel 260, a monitor 280, animaging probe 230 connected to the central station 250 by wire 232A, andan interventional medical device 205 connected to the central station bywire 212A. The interventional medical device 205 in FIG. 2A includes asheath S and a wire W. A movable sensor MS is movable with a tool T atthe end of the wire W of the interventional medical device 205. Thesensor MS is movable with tool T at the end of the wire W of theinterventional medical device 205, but does not necessarily have to beprovided either with a tool T distinguishable from the interventionalmedical device 205, or at an extremity of any portion of theinterventional medical device 205. A fixed location F is disposed on, oras part of, the sheath S of the interventional medical device 205, andmay be a visual marker, a fixed sensor, or another form of fixture thatcan be used to help in determining relative movement of the sensor MS.

By way of explanation, an interventional medical device 205 is placedinternally into a patient during a medical procedure. Locations of theinterventional medical device 205 can be tracked using the movablesensor MS and fixed location F. Moreover, the relationship between themovable sensor MS and fixed location F can be used to determine theshape of the interventional medical device 205. The relationship of theinterventional medical device 205, the tool T, the movable sensor MS andthe fixed location F may vary greatly from what is shown in FIG. 2A andFIG. 2B. Similarly, the shape of each of the interventional medicaldevice 205, the tool T, the movable sensor MS and the fixed location Fmay vary greatly from what is shown in FIG. 2A and FIG. 2B.

For example, the movable sensor MS may receive ultrasound tracking beamsto help determine a location of the movable sensor MS. Ultrasoundtracking beams described herein may be ultrasound imaging beams that areotherwise used to obtain ultrasound images, or may be ultrasoundtracking beams that are separate (e.g., separate frequencies, separatetransmission timing) from the ultrasound imaging beams. The movablesensor MS may be used passively or actively to respond to the receivedultrasound tracking beams. As described herein, ultrasound imaging beamsand/or ultrasound tracking beams separate from the ultrasound imagingbeams can be used to selectively, typically, or always obtain a locationof the movable sensor MS. However, as also noted herein, the trackingcan be performed using either or both of the ultrasound imaging beams orcompletely separate ultrasound tracking beams.

In FIG. 2A, wire 212A and wire 232A are used to connect theinterventional medical device 205 and imaging probe 230 to the centralstation 250. For the imaging probe 230, a wire 232A may not present muchof a concern, though the wire 232A may still be a distraction. For theinterventional medical device 205, a wire 212A may be used to send back,for example, images when the interventional medical device 205 is usedto capture images. However, a wire 212A may be of more concern in thatthe interventional medical device 205 is at least partly inserted in thepatient. Accordingly, replacing the wire 232A and the wire 212A withwireless connections may provide some benefit.

FIG. 2B illustrates another ultrasound system for sensor-based shapeidentification, in accordance with a representative embodiment.

In FIG. 2B, the wire 232A is replaced with wireless data connection232B, and the wire 212A is replaced with wireless data connection 212B.Otherwise, the ultrasound system 200 in FIG. 2B includes the samecentral station 250 as in FIG. 2A, i.e., with the processor 251 andmemory 252, touch panel 260, monitor 280, imaging probe 230, andinterventional medical device 205. The interventional medical device 205in FIG. 2B also includes the sheath S and the wire W. The movable sensorMS is movable with the tool T at the end of the wire W of theinterventional medical device 205.

In FIG. 2B, the ultrasound system 200 may be an arrangement with aninterventional medical device 205 with the movable sensor MS and thefixed location F on board. The interventional medical device 205 mayinclude, e.g., a needle with the movable sensor MS at or near its tip.The movable sensor MS may also be configured to listen to and analyzedata from tracking beams, such that the “sending” of the tracking beamsfrom the imaging probe 230, and the “listening” to the tracking beams bythe movable sensor MS, are synchronized. Use of tracking beams separatefrom imaging beams may be provided in an embodiment, but not the primaryembodiment(s) of the present disclosure insofar as sensor-based shapeidentification primarily uses embodiments with only imaging beams.

In FIG. 2A or FIG. 2B, the imaging probe 230 may send a pulse sequenceof imaging beams. An explanation of the relationship between the centralstation 250, imaging probe 230 and the movable sensor MS and fixedlocation F follows. In this regard, central station 250 in FIGS. 2A and2B may include a beamformer (not shown) that is synchronized by a clock(not shown) to send properly delayed signals in a transmit mode toelements of an imaging array in the imaging probe 230. In a receivemode, the beamformer may properly delay and sum signals from theindividual elements of the imaging array in the imaging probe 230. Theultrasound imaging itself is performed using the imaging probe 230, andmay be in accordance with beamforming performed by the beamformer of thecentral station 250.

The imaging probe 230 may emit imaging beams as tracking beams thatimpinge on the movable sensor MS (i.e., when the movable sensor MS is inthe field of view of the tracking beams). The movable sensor MS mayreceive and convert the energy of the tracking beams into signals sothat the movable sensor MS, or even the interventional medical device205, can determine the position of the movable sensor MS relative to theimaging array of the imaging probe 230. The relative position of themovable sensor MS can be computed geometrically based on the receivedtracking beams received by the movable sensor MS, and the relativepositions over a period of time can be used to identify the shape of theinterventional medical device 205 as it is deployed in a patient.

The fixed location F may be a visual marker fixed, for example, on thesheath at a fixed location. A visual marker may be distinguishable fromtissue, such as when the visual marker is made from a material that willreflect and/or absorb energy from the imaging beams in a mannerdistinguishable from the way that tissue reflects and/or absorbs energyfrom the imaging beams. In this way, a visual marker can be identifiedautomatically through image processing from the ultrasound images.However, the fixed location F may also be a fixed sensor such as apassive ultrasound sensor. The imaging beams from the imaging probe 230may impinge on the fixed sensor at the fixed location F when the fixedsensor is in the field of view of the imaging beams as tracking beams.The fixed sensor at the fixed location F may receive and convert theenergy of the imaging beams as tracking beams into signals so that thefixed sensor at the fixed location F, or even the interventional medicaldevice 205, can repeatedly determine the position of the fixed sensor atthe fixed location F relative to the imaging array of the imaging probe230. Thus, the imaging probe 230 emits tracking beams to theinterventional medical device 205 for a period of time that includesmultiple different points of time. For example, tracking beams may beemitted for 30 seconds, 60 seconds, 120 seconds, 180 seconds or anyother period of time that include multiple different points of time.Responses to the tracking beams may be collected periodically, such asevery second or every 1/10th second. The responses to the tracking beamsmay be reflected energy reflected by the movable sensor MS and the fixedsensor at the fixed location F. Alternatively, the responses to thetracking beams may be active signals generated by the movable sensor MSand the fixed sensor at the fixed location F, such as readings of thereceived energy of the tracking beams.

The fixed location F may also be a visual marker that may bedistinguishable from tissue in ultrasound imaging. The fixed location Fmay also be a marker whose position in space is detectable with respectto anatomy by an alternative modality of imaging, for example X-rayimaging, computed tomography imaging, MRI imaging, optical imaging, ordirect visualization. The fixed location F may be a marker whoseposition in space is detectable with respect to anatomy by analternative method of sensing such as Doppler ultrasound,electromagnetic tracking, or laser tracking wherein an image is notexplicitly generated. Finally, the fixed location F may be a locationthat is not directly detected by external means, but whose position inspace is known at all times with respect to anatomy.

In other embodiments, rather than the fixed location F being tracked bythe mechanisms described above (i.e., other than passive ultrasoundsensor), the moving sensor MS may be tracked by such means. In theseembodiments, the fixed location F may be or include a passive ultrasoundsensor tracked by, e.g., Insitu.

Based on the responses to the tracking beams, the processor 251 maydetermine, for example, absolute position of the movable sensor MS andthe fixed sensor at the fixed location F at each of multiple differentpoints in time during the period of time. As a result, movement of themovable sensor MS relative to the fixed sensor at the fixed location Fcan be determined. The movement reveals the path of the movable sensorMS relative to the fixed location F. And the path reveals the shape ofthe interventional medical device 205 insofar as the movement of themovable sensor MS relative to the fixed sensor at the fixed location Fmay correspond to the shape of the interventional medical device 205 isinserted or otherwise moved into the body of the patient. Thus, orinstance, when the movable sensor MS is on a needle or a wire as thetool T, the movable sensor MS may move with the needle or wire from asheath S, such that the movable sensor MS moves relative to the fixedlocation F on the interventional medical device.

The central station 250 may be considered a control unit or controllerthat controls the imaging probe 230. As described in FIGS. 2A and 2B,the central station 250 includes a processor 251 connected to a memory252. The central station 250 may also include a clock (not shown) whichprovides clock signals to synchronize the imaging probe 230 with themovable sensor MS. Moreover, one or more elements of the central station250 may individually be considered a control unit or controller. Forexample, the combination of the processor 251 and the memory 252 may beconsidered a controller that executes software to perform processesdescribed herein, i.e., to use positions of the movable sensor MS todetermine shape of the interventional medical device 205 as theinterventional medical device 205 is deployed in a patient.

The imaging probe 230 is adapted to scan a region of interest thatincludes the interventional medical device 205, the movable sensor MSand the fixed location F. Of course, as is known for ultrasound imagingprobes, the imaging probe 230 uses ultrasound imaging beams to provideimages on a frame-by-frame basis. The imaging probe 230 can also useseparate tracking beams to obtain the location of the movable sensor MSand the fixed location F.

In a one-way relationship, the movable sensor MS and a fixed sensor atthe fixed location F may be adapted to convert tracking beams providedby the imaging probe 230 into electrical signals. The movable sensor MSand the fixed sensor at the fixed location F may be configured toprovide either the raw data or partially or completely processed data(e.g., calculated sensor locations) to the central station 250, eitherdirectly or indirectly (e.g., via a transmitter or repeater located in aproximal end of the interventional medical device 205). These data,depending on their degree of processing, are either used by the centralstation 250 to determine the location of the movable sensor MS (and thelocation of the distal end of the interventional medical device 205 towhich the movable sensor MS is attached) and the fixed sensor at thefixed location F, or to provide the central station 250 with thelocation of the movable sensor MS (and the location of the distal end ofthe interventional medical device 205 to which the movable sensor MS isattached) and the fixed sensor at the fixed location F. The locationsfrom multiple different readings at different times in a period are usedto determine shape of the interventional medical device 205, and areaccurate insofar as movement of the imaging probe 230 or tissue isaccounted for by subtracting or otherwise factoring out the locations ofthe fixed sensor at the fixed location F.

As described herein, the positions of the movable sensor MS and fixedsensor at the fixed location F are determined by or provided to thecentral station 250. The positions of the movable sensor MS and thefixed sensor at the fixed location F can be used by the processor 251 tooverlay the positions of the movable sensor MS and the fixed sensor atthe fixed location F onto an image frame for display on the monitor 280.As a result, movement of the movable sensor, and thus the distal end ofthe interventional medical device 205, over time relative to the fixedsensor at the fixed location F shows the shape of the interventionalmedical device 205 as the tool T moves with the end of the wire W. Theposition of the fixed sensor at the fixed location F can be used toadjust the position of the movable sensor MS, such as to factor outmovement of tissue that affects the locations of the movable sensor MSin an absolute coordinate system. In other words, a movable sensor MSmay move relative to a fixed location F based on movement of tissue thatcontacts the movable sensor MS, in addition to operational movement ofthe movable sensor MS with the tool T at the end of the wire W. Inanother representative embodiment, instructions stored in memory 252 areexecuted by the processor 251 to determine positions of the movablesensor MS and the fixed sensor at the fixed location F relative to animage frame, and to overlay the positions of the movable sensor MS andthe fixed sensor at the fixed location F. Accordingly, the shape of theinterventional medical device 205 is derived from the changing locationsof the movable sensor MS relative to the fixed sensor at the fixedlocation F, as the tool T moves with the end of the wire W. Again, thelocations of the fixed sensor at the fixed location F can be factoredout to account for movement of tissue or even movement of the imagingprobe 230 that affects the perceived location of the movable sensor MSin an absolute coordinate system.

Broadly, in operation, the processor 251 initiates a scan by the imagingprobe 230. The scan can include emitting imaging beams as tracking beamsacross a region of interest. The imaging beams are used to form an imageof a frame; and as tracking beams to determine the location of themovable sensor MS and the fixed sensor at the fixed location F. Thelocations in turn are used to determine shape as the movable sensor MSmoves relative to the fixed location F over a period of time. As can beappreciated, the image from imaging beams is formed from a two-waytransmission sequence, with images of the region of interest beingformed by the transmission and reflection of sub-beams. Additionally, ina one-way relationship, the imaging beams as tracking beams incident onthe movable sensor MS and the fixed sensor at the fixed location F andmay be converted into electrical signals (i.e., rather than or inaddition to reflecting the tracking beams). In a two-way relationship,the imaging beams as tracking beams are reflected by the movable sensorMS and the fixed sensor at the fixed location F, so that the imagingprobe 230 determines the location of the movable sensor MS and the fixedsensor at the fixed location F using the reflected tracking beams.

As noted above, data used to determine locations of the movable sensorMS and the fixed sensor at the fixed location F may comprise raw data,partially processed data, or fully processed data, depending on wherelocation is to be determined. Depending on the degree of processing,these data can be provided to the processor 251 for executinginstructions stored in the memory 252 (i.e., of the central station 250)to determine the positions of the movable sensor MS and the fixed sensorat the fixed location F in the coordinate system of ultrasound imagesfrom the beamformer. Alternatively, these data may include thedetermined positions of the movable sensor MS and the fixed sensor atthe fixed location F in the coordinate system which is used by theprocessor 251 when executing instructions stored in the memory 252 tooverlay the positions of the movable sensor MS and the fixed sensor atthe fixed location F on the ultrasound image in the monitor 280. To thisend, the beamformer of the central station 250 may process thebeamformed signal for display as an image of a frame. The output fromthe beamformer can be provided to the processor 251. The data from themovable sensor MS and the fixed sensor at the fixed location F may beraw data, in which case the processor 251 executes instructions in thememory 252 to determine the positions of the movable sensor MS and thefixed sensor at the fixed location F in the coordinate system of theimage; or the data from the movable sensor MS and the fixed sensor atthe fixed location F may be processed by the interventional medicaldevice 205 to determine the locations of the movable sensor MS and thefixed sensor at the fixed location F in the coordinate system of theimage. Either way, the processor 251 is configured to overlay thepositions of the movable sensor MS and the fixed sensor at the fixedlocation F on the image on the monitor 280. For example, a compositeimage from the imaging beams as tracking beams may include the image oftissue and actual or superposed positions of the movable sensor MS andthe fixed sensor at the fixed location F, thereby providing real-timefeedback to a clinician of the position and history of the movablesensor MS (and the distal end of the interventional medical device 205)and the fixed sensor at the fixed location F, each relative to theregion of interest and to each other. As can be appreciated, superposingof the positions of the movable sensor MS in context with historicalpositions and in context of the fixed sensor at the fixed location F,enables complete real-time in-situ visualization of shape of theinterventional medical device 205 as the movable sensor MS projects fromthe interventional medical device with, e.g., the wire W or tool T.

FIG. 2C is an illustrative embodiment of a general computer system, onwhich a method of sensor-based shape identification can be implemented,in accordance with a representative embodiment.

The computer system 2100 can include a set of instructions that can beexecuted to cause the computer system 2100 to perform any one or more ofthe methods or computer based functions disclosed herein. The computersystem 2100 may operate as a standalone device or may be connected, forexample, using a network 2101, to other computer systems or peripheraldevices. Any or all of the elements and characteristics of the computersystem 2100 in FIG. 1C may be representative of elements andcharacteristics of the central station 250, the imaging probe 230, oreven the movable sensor MS and the fixed sensor at the fixed location Fin FIGS. 2A and 2B.

In a networked deployment, the computer system 2100 may operate in thecapacity of a client in a server-client user network environment. Thecomputer system 2100 can also be fully or partially implemented as orincorporated into various devices, such as a control station, imagingprobe, passive ultrasound sensor, stationary computer, a mobilecomputer, a personal computer (PC), or any other machine capable ofexecuting a set of instructions (sequential or otherwise) that specifyactions to be taken by that machine. The computer system 2100 can beincorporated as or in a device that in turn is in an integrated systemthat includes additional devices. In an embodiment, the computer system2100 can be implemented using electronic devices that provide video ordata communication. Further, while the computer system 2100 isillustrated, the term “system” shall also be taken to include anycollection of systems or sub-systems that individually or jointlyexecute a set, or multiple sets, of instructions to perform one or morecomputer functions.

As illustrated in FIG. 1C, the computer system 2100 includes a processor2110. A processor 2110 for a computer system 2100 is tangible andnon-transitory. As used herein, the term “non-transitory” is to beinterpreted not as an eternal characteristic of a state, but as acharacteristic of a state that will last for a period. The term“non-transitory” specifically disavows fleeting characteristics such ascharacteristics of a carrier wave or signal or other forms that existonly transitorily in any place at any time. Any processor describedherein is an article of manufacture and/or a machine component. Aprocessor for a computer system 2100 is configured to execute softwareinstructions to perform functions as described in the variousembodiments herein. A processor for a computer system 2100 may be ageneral-purpose processor or may be part of an application specificintegrated circuit (ASIC). A processor for a computer system 2100 mayalso be a microprocessor, a microcomputer, a processor chip, acontroller, a microcontroller, a digital signal processor (DSP), a statemachine, or a programmable logic device. A processor for a computersystem 2100 may also be a logical circuit, including a programmable gatearray (PGA) such as a field programmable gate array (FPGA), or anothertype of circuit that includes discrete gate and/or transistor logic. Aprocessor for a computer system 2100 may be a central processing unit(CPU), a graphics processing unit (GPU), or both. Additionally, anyprocessor described herein may include multiple processors, parallelprocessors, or both. Multiple processors may be included in, or coupledto, a single device or multiple devices.

Moreover, the computer system 2100 includes a main memory 2120 and astatic memory 2130 that can communicate with each other via a bus 2108.Memories described herein are tangible storage mediums that can storedata and executable instructions, and are non-transitory during the timeinstructions are stored therein. As used herein, the term“non-transitory” is to be interpreted not as an eternal characteristicof a state, but as a characteristic of a state that will last for aperiod. The term “non-transitory” specifically disavows fleetingcharacteristics such as characteristics of a carrier wave or signal orother forms that exist only transitorily in any place at any time. Amemory described herein is an article of manufacture and/or machinecomponent. Memories described herein are computer-readable mediums fromwhich data and executable instructions can be read by a computer.Memories as described herein may be random access memory (RAM), readonly memory (ROM), flash memory, electrically programmable read onlymemory (EPROM), electrically erasable programmable read-only memory(EEPROM), registers, a hard disk, a removable disk, tape, compact diskread only memory (CD-ROM), digital versatile disk (DVD), floppy disk,blu-ray disk, or any other form of storage medium known in the art.Memories may be volatile or non-volatile, secure and/or encrypted,unsecure and/or unencrypted.

As shown, the computer system 2100 may further include a video displayunit 2150, such as a liquid crystal display (LCD), an organic lightemitting diode (OLED), a flat panel display, a solid-state display, or acathode ray tube (CRT). Additionally, the computer system 2100 mayinclude an input device 2160, such as a keyboard/virtual keyboard ortouch-sensitive input screen or speech input with speech recognition,and a cursor control device 2170, such as a mouse or touch-sensitiveinput screen or pad. The computer system 2100 can also include a diskdrive unit 2180, a signal generation device 2190, such as a speaker orremote control, and a network interface device 2140.

In an embodiment, as depicted in FIG. 1C, the disk drive unit 2180 mayinclude a computer-readable medium 2182 in which one or more sets ofinstructions 2184, e.g. software, can be embedded. Sets of instructions2184 can be read from the computer-readable medium 2182. Further, theinstructions 2184, when executed by a processor, can be used to performone or more of the methods and processes as described herein. In anembodiment, the instructions 2184 may reside completely, or at leastpartially, within the main memory 2120, the static memory 2130, and/orwithin the processor 2110 during execution by the computer system 2100.

In an alternative embodiment, dedicated hardware implementations, suchas application-specific integrated circuits (ASICs), programmable logicarrays and other hardware components, can be constructed to implementone or more of the methods described herein. One or more embodimentsdescribed herein may implement functions using two or more specificinterconnected hardware modules or devices with related control and datasignals that can be communicated between and through the modules.Accordingly, the present disclosure encompasses software, firmware, andhardware implementations. Nothing in the present application should beinterpreted as being implemented or implementable solely with softwareand not hardware such as a tangible non-transitory processor and/ormemory.

In accordance with various embodiments of the present disclosure, themethods described herein may be implemented using a hardware computersystem that executes software programs. Further, in an exemplary,non-limited embodiment, implementations can include distributedprocessing, component/object distributed processing, and parallelprocessing. Virtual computer system processing can be constructed toimplement one or more of the methods or functionality as describedherein, and a processor described herein may be used to support avirtual processing environment.

The present disclosure contemplates a computer-readable medium 2182 thatincludes instructions 2184 or receives and executes instructions 2184responsive to a propagated signal; so that a device connected to anetwork 2101 can communicate video or data over the network 2101.Further, the instructions 2184 may be transmitted or received over thenetwork 2101 via the network interface device 2140.

FIG. 3 illustrates an interventional medical device used forsensor-based shape identification, in accordance with a representativeembodiment.

Sensor-based shape identification can be used to quantify a shape usingpassive ultrasound sensors as shown in FIG. 3 . A movable sensor MS is afirst sensor that is movable along a first device to obtain the shape ofthe first device. The movable sensor MS moves as a wire W is drawn froma sheath S. A fixed sensor at a fixed location F is a second sensorlocated on a second device and remains static with respect to anatomy.The fixed sensor at the fixed location F remains stationary in both thehorizontal (X) plane and the vertical (Y) plane as the wire W is drawnfrom the sheath S. In three-dimensional ultrasound, the fixed sensorremains stationary in the horizontal (X) plane, the vertical (Y) plane,and the depth (Z) plane, and the movable sensor is tracked in all threeof these planes to obtain the three-dimensional shape. The fixed sensorat the fixed location F serves as a fixed reference marker, e.g. tocompensate for tissue or probe motion. In other words, the movablesensor MS is a first sensor that moves relative to a second sensor fixedat a fixed location F for a period of time. In FIG. 3 , the movablesensor MS is shown to move at five different positions at differenttimes, i.e., t=1, t=2, t=3, t=4, and t=5 in a period. A pullback orother related motion of the movable sensor MS as the first sensorrelative to the fixed sensor fixed at the fixed location F is tracked,and the tracking position history is integrated to obtain shape. Thelocations can be tracked using methodology such as the InSitumethodology which tracks passive ultrasound sensors with either imagingbeams alone, or with imaging beams and completely separate trackingbeams such as interleaved separate imaging beams and tracking beams.

The fixed location F may also be a visual marker or a marker that isdetectable by an alternative modality of imaging or sensing, includingbut not limited to X-ray imaging, computed tomography imaging, MRIimaging, optical imaging, Doppler ultrasound, electromagnetic tracking,laser tracking or direct visualization, or a marker whose position inspace is known at all times with respect to anatomy without explicitsensing.

In FIG. 3 , the device containing the movable sensor MS as the firstsensor is a wire, and the device containing the fixed sensor fixed atthe fixed location F as the second sensor is a conduit or sheath.However, the reverse mechanism is also possible. The fixed sensor as thesecond sensor may also be referred to as a reference sensor.

Specifically, in FIG. 3 , the first device containing the movable sensorMS is a wire, and the second device containing the fixed sensor (i.e.,the reference sensor) is a conduit or sheath. The movable sensor as thefirst sensor is tracked as the wire is moved along the inner channel ofthe sheath, and the fixed sensor as the second sensor stays fixedrelative to anatomy.

The inverse of the mechanism in FIG. 3 is also possible. Here, a fixedwire containing the fixed sensor as the second sensor (i.e., thereference sensor) is positioned within a movable outer sheath containingthe movable sensor as the first sensor.

FIGS. 4A-4D together explain three-dimensional shape quantification ofan implantable mitral valve during deployment.

FIG. 4A illustrates an interventional medical device used forsensor-based shape identification, in accordance with a representativeembodiment. Whereas the mechanism of FIG. 3 can be tightly integratedwith the physical deployment of any device to allow the user to easilydeploy a device and obtain the shape/path of the deployment in a singlestep without needing to perform a manual pullback, an exampleapplication of the device is shown in FIG. 4A, where the mechanism isintegrated with an implantable mitral valve. The working channel of themitral valve serves as the sheath S which is a sheath and/or conduit.The wire W is an implant guidewire that contains the movable sensor MSas the first sensor, and as the wire W is deployed within the valve,shape is tracked using three-dimensional ultrasound.

Similarly, deployment of the mechanism of FIG. 4A can be automated in amanner that allows discrimination between tissue movement and probemovement. When the pullback velocity is controlled, probe and tissuemotion can be differentiated from the deployment more clearly. That is,tissue motions will result in deviations from the controlled andtherefore expected velocities of the moving sensor MS to the fixedsensor at the fixed location F, or deviations from the expected changesin measured distance, whereas probe motions will not result in suchdeviations from expected measurements of such velocities or distances. Acontroller can measure movement of the imaging probe based on movementtogether of the first sensor and the second sensor, as well as based onmovement of the first sensor relative to the second sensor. That is, acontroller can measure when either sensor moves with or relative to theother, or when a sensor and a fixed location moves with or relative tothe other.

In FIG. 4A, a mitral valve device includes a working channel as thesheath S and a guidewire as the wire W. The moving sensor MS isimplanted on or in the guidewire as the wire W, and the fixed sensor atthe fixed location F is on or in the working channel as the sheath S.

FIG. 4B illustrates operation of the interventional medical device usedfor sensor-based shape identification in FIG. 4A, in accordance with arepresentative embodiment.

FIG. 4B shows that, as the mitral valve device is deployed, theguidewire as the wire W is moved along the inner working channel of thedevice as the sheath S. The distal end of the working channel as thesheath S contains the fixed reference sensor as the fixed sensor at thefixed location F, and shape is determined based on either forward orpullback movement of the wire W.

FIG. 4C illustrates an operation of the interventional medical deviceused for sensor-based shape identification in FIG. 4A, in accordancewith a representative embodiment. In FIG. 4C, a target anatomy A, forexample a mitral valve, is difficult to visualize directly in athree-dimensional (3D) ultrasound image. This illustrates why adistinctive visualization of the shape can be useful, such as when theshape of anatomy A is highlighted by color or lighting so as to offsetthe shape of anatomy A relative to the ultrasound image of tissue.

FIG. 4D illustrates another operation of the interventional medicaldevice used for sensor-based shape identification in FIG. 4A, inaccordance with a representative embodiment. In FIG. 4D, thethree-dimensional (3D) ultrasound image with segmentation overlay basedon shape from InSitu shows the interventional medical device and atarget anatomy A, such as a mitral valve, much more clearly than in FIG.4C.

FIG. 5 illustrates a process for sensor-based shape identification, inaccordance with a representative embodiment. In FIG. 5 , the processstarts at S510 by transmitting one or more tracking beams. At S520, theresponse to the tracking beams is received. At S530, positions and/orcoordinates of a second sensor are identified over a period of timebased on a response to tracking beams, to provide sensor location of thesecond sensor for each of multiple points in time. At S540, positionsand/or coordinates of a first sensor are identified over a period oftime based on a response to tracking beams, to provide sensor locationof the first sensor for each of the multiple points in time. At S550, ashape of the interventional device is determined based on movement ofthe second sensor relative to the first sensor over the period of time.

FIG. 6 illustrates another process for sensor-based shapeidentification, in accordance with a representative embodiment.

The process in FIG. 6 starts by transmitting tracking beams at S610. AtS620, a response to the tracking beams is received. At S630, positionsand/or coordinates of a second sensor are identified over a period oftime based on a response to the tracking beams. At S640, positionsand/or coordinates of a first sensor are identified over a period oftime based on a response to the tracking beams. At S650, positionsand/or coordinates of the second sensor and first sensor are stored. AtS660, positions and/or coordinates of the second sensor and first sensorare displayed. At S670, a determination is made whether the response tothe tracking beams is the last response. If the response to the trackingbeams at S620 is not the last response (S670=No), the process returns toS630 to again identify positions and/or coordinates of a second sensorover a period of time based on a response to the tracking beams. If theresponse to the tracking beams at S620 is the last response (S670=Yes),at S680 the shape of the interventional device is determined based onstored/displayed positions of the second sensor and the first sensor.

Although not illustrated in FIG. 6 , the determined shape of aninterventional device can be automatically or visually compared with anexpected shape of the interventional device to ensure the interventionaldevice is progressing properly. For example, the process may includegenerating and projecting an expected shape of the interventionalmedical device before controlling the imaging probe, and then comparingthe shape of the interventional medical device with the expected shapeafter determining the shape of the interventional medical device.Similarly, the process may include generating and projecting an expectedpath of the interventional medical device or an expected path of themoving sensor and then comparing the path of the interventional medicaldevice or the path of the moving sensor to the expected path.

FIG. 7 illustrates a sequence in which fixed sensor can be used toisolate probe motion for sensor-based shape identification, inaccordance with a representative embodiment.

For situations in which both sensors are static, probe and tissue motioncan again be differentiated, since probe motion will cause both sensorsto move together whereas tissue motion likely will not (see FIG. 7 ).Specifically, when both sensors are static, tissue motions will resultin variation of the measured moving-to-fixed sensor distance, whereasprobe motions will not affect the sensor distance. A controller canmeasure movement of the imaging probe based on movement together of thefirst sensor and the second sensor, as well as based on movement of thefirst sensor relative to the second sensor.

For structural heart applications, the described mechanism can also beused to directly determine the cardiac cycle/cardiac motion. Here, asthe position profiles of one or both the sensors are tracked over time,cyclical patterns in the temporal profile can be observed. The phase ofthe motion profiles indicates the cardiac cycles, and the magnitude ofposition change can be used to estimate cardiac motion. Notably, cardiacmotion is not provided by ECG alone, but can be estimated from themagnitude of position change.

As noted above, when both sensors are static, tissue motions will resultin variation of the measured moving-to-fixed sensor distance, whereasprobe motion will not affect the sensor distance. Similarly, duringautomated pullback where the velocity is known, tissue motions willresult in deviations of the measured moving-to-fixed velocity (or changein measured distance) from the known velocity (or changed in measureddistance), whereas probe motions will not result in such deviations. Thesame principles apply when the pullback motion is coupled with devicedeployment.

As an example, sensor-based shape identification can be used for andwith image-guided therapy (IGT) systems and devices. Sensor-based shapeidentification can be used to check that an interventional device hasthe correct shape and path during deployment, to detect an irregularpath during an invasive procedure (e.g., septal puncture or chronictotal occlusion crossing), to quantify a three-dimensional shape ofimplants (e.g., mitral valve implants) during tissue/organ repair (e.g.,structural heart repair), and even to directly estimate cardiaccycle/cardiac motion using a static reference sensor.

Although sensor-based shape identification has been described withreference to several exemplary embodiments, it is understood that thewords that have been used are words of description and illustration,rather than words of limitation. Changes may be made within the purviewof the appended claims, as presently stated and as amended, withoutdeparting from the scope and spirit of sensor-based shape identificationin its aspects. Although sensor-based shape identification has beendescribed with reference to particular means, materials and embodiments,sensor-based shape identification is not intended to be limited to theparticulars disclosed; rather sensor-based shape identification extendsto all functionally equivalent structures, methods, and uses such as arewithin the scope of the appended claims.

For example, sensor-based shape identification can be used in structuralheart repair, such as to check to ensure correct shape/path duringdevice deployment, to detect whether the device has left a desired pathduring invasive procedures such as septal punctures, to quantifythree-dimensional shape of mitral valve and other implants duringstructural heart repair, to directly estimate the cardiac cycle/cardiacmotion using the static reference sensor, and/or to differentiatecardiac motion versus probe motion based on the relative position andvelocity between sensors. An example of detecting whether the device hasleft a desired path during invasive procedures may involve, for example,a reference marker being placed at the location of the target anatomy.

In another example, sensor-based shape identification can be used forperipheral vascular intervention, such as to monitor wire shape duringstenosis or occlusion crossings to detect wire buckling, and/or todetect wire progression with respect to the vessel to check if the wirehas exited the vessel wall.

In other examples involving interventional procedures, sensor-basedshape identification can be used to detect needle bending during deeptissue biopsy, and/or to provide a reliable in-body two-dimensional (2D)projection or three-dimensional (3D) projection fiducial registering theultrasound to external imaging modalities, including but not limited toX-ray imaging, optical imaging, or computed tomography imaging.

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of the disclosuredescribed herein. Many other embodiments may be apparent to those ofskill in the art upon reviewing the disclosure. Other embodiments may beutilized and derived from the disclosure, such that structural andlogical substitutions and changes may be made without departing from thescope of the disclosure. Additionally, the illustrations are merelyrepresentational and may not be drawn to scale. Certain proportionswithin the illustrations may be exaggerated, while other proportions maybe minimized. Accordingly, the disclosure and the figures are to beregarded as illustrative rather than restrictive.

One or more embodiments of the disclosure may be referred to herein,individually and/or collectively, by the term “invention” merely forconvenience and without intending to voluntarily limit the scope of thisapplication to any particular invention or inventive concept. Moreover,although specific embodiments have been illustrated and describedherein, it should be appreciated that any subsequent arrangementdesigned to achieve the same or similar purpose may be substituted forthe specific embodiments shown. This disclosure is intended to cover anyand all subsequent adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be usedto interpret or limit the scope or meaning of the claims. In addition,in the foregoing Detailed Description, various features may be groupedtogether or described in a single embodiment for the purpose ofstreamlining the disclosure. This disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter may be directed toless than all of the features of any of the disclosed embodiments. Thus,the following claims are incorporated into the Detailed Description,with each claim standing on its own as defining separately claimedsubject matter.

The preceding description of the disclosed embodiments is provided toenable any person skilled in the art to practice the concepts describedin the present disclosure. As such, the above disclosed subject matteris to be considered illustrative, and not restrictive, and the appendedclaims are intended to cover all such modifications, enhancements, andother embodiments which fall within the true spirit and scope of thepresent disclosure. Thus, to the maximum extent allowed by law, thescope of the present disclosure is to be determined by the broadestpermissible interpretation of the following claims and theirequivalents, and shall not be restricted or limited by the foregoingdetailed description.

The invention claimed is:
 1. A controller for determining shape of aninterventional medical device, the controller comprising: a processorcommunicatively coupled to memory, the processor configured to: controlan imaging probe to emit at least one tracking imaging beam to theinterventional medical device over a period of time comprising aplurality of different points in time; receive, at each of the pluralityof different points in time, a response to the at least one trackingimaging beam from a first sensor fixed on a first portion of theinterventional medical device and a second sensor fixed at a fixedlocation on a second portion of the interventional medical device,wherein, during the period of time, the first portion, with the firstsensor, moves along the interventional medical device relative to thesecond sensor at the fixed location; determine a plurality of positionsof the first sensor corresponding to the plurality of different pointsin time based on the received response to the at least one trackingimaging beam from the first sensor; determine a path of movement of thefirst sensor relative to the second sensor based on the plurality ofpositions of the first sensor at the plurality of different points intime; and derive a shape of the interventional medical device based onthe determined path of movement of the first sensor relative to thesecond sensor.
 2. The controller of claim 1, wherein: the first sensormoves relative to the second sensor by the first portion being movedrelative to the second portion.
 3. The controller of claim 2, whereinthe first sensor is fixed in position on the first portion, and thefirst sensor moves relative to the second sensor by the first portionbeing moved relative to the second portion.
 4. The controller of claim1, wherein the first portion with the first sensor is movable within thesecond portion.
 5. The controller of claim 1, wherein the second portionwith the second sensor is moveable within the first portion.
 6. Thecontroller of claim 1, wherein the first portion comprises a wire andthe second portion comprises a conduit or sheath.
 7. The controller ofclaim 1, wherein the processor is further configured to: detect a changein position of the second sensor indicating at least one of tissuemotion and imaging probe motion, provide adjustment to one or more ofthe determined plurality of positions of the first sensor based on thechanged position of the second sensor to compensate for the at least oneof tissue motion and imaging probe motion, and determine the path ofmovement to account for the adjustment to the one or more of thedetermined plurality of positions of the first sensor.
 8. A method fordetermining shape of an interventional medical device, comprising:controlling an imaging probe to emit at least one tracking imaging beamto an interventional medical device over a period of time comprising aplurality of different points in time; receiving, at each of theplurality of different points in time, a response to the at least onetracking imaging beam from a first sensor fixed on a first portion ofthe interventional medical device and a second sensor fixed at a fixedlocation on a second portion of the interventional medical device,wherein-during the period of time, the first portion, with the firstsensor, moves along the interventional medical device relative to thesecond sensor at the fixed location; determining a plurality ofpositions of the first sensor corresponding to the plurality ofdifferent points in time based on the received response to the at leastone tracking imaging beam from the first sensor; determining a path ofmovement of the first sensor relative to the second sensor based on theplurality of positions of the first sensor at the plurality of differentpoints in time; and deriving a shape of the interventional medicaldevice based on the determined path of movement of the first sensorrelative to the second sensor.
 9. The method of claim 8, wherein: thefirst sensor moves relative to the second sensor by the first portionbeing moved relative to the second portion.
 10. The method of claim 9,wherein the first sensor is fixed in position on the first portion, andthe first sensor moves relative to the second sensor by the firstportion being moved relative to the second portion.
 11. The method ofclaim 8, wherein the first portion with the first sensor is movablewithin the second portion.
 12. The method of claim 8, wherein the secondportion with the second sensor is movable within the first portion. 13.The method of claim 8, further comprising: projecting an expected shapeof the interventional medical device before controlling the imagingprobe; and comparing the shape of the interventional medical device withthe expected shape after determining the shape of the interventionalmedical device.
 14. The method of claim 8, further comprising: receivingthe response to the at least one tracking imaging beam from the firstsensor and the second sensor fixed at the fixed location.
 15. The methodof claim 8, further comprising: detecting a change in position of thesecond sensor indicating at least one of tissue motion and imaging probemotion, providing adjustment to one or more of the determined pluralityof positions of the first sensor based on the changed position of thesecond sensor to compensate for the at least one of tissue motion andimaging probe motion, and determining the path of movement to accountfor the adjustment to the one or more of the determined plurality ofpositions of the first sensor.
 16. A non-transitory computer-readablestorage medium comprising instructions which, when executed by aprocessor, cause the processor to: control an imaging probe to emit atleast one tracking imaging beam to an interventional medical device overa period of time comprising a plurality of different points in time;receive, at each of the plurality of different points in time, aresponse to the at least one tracking imaging beam from a first sensorfixed on a first portion of the interventional medical device and asecond sensor fixed at a fixed location on a second portion of theinterventional medical device, wherein during the period of time, thefirst portion, with the first sensor, moves along the interventionalmedical device relative to the second sensor at the fixed location;determine a plurality of positions of the first sensor corresponding tothe plurality of different points in time based on the received responseto the at least one tracking imaging beam from the first sensor;determine a path of movement of the first sensor relative to the secondsensor based on the plurality of positions of the first sensor at theplurality of different points in time; and derive a shape of theinterventional medical device based on the determined path of movementof the first sensor relative to the second sensor.
 17. Thenon-transitory computer-readable storage medium of claim 16, wherein theinstructions, when executed by the processor, further cause theprocessor to: detect a change in position of the second sensorindicating at least one of tissue motion and imaging probe motion,provide adjustment to one or more of the determined plurality ofpositions of the first sensor based on the changed position of thesecond sensor to compensate for the at least one of tissue motion andimaging probe motion, and determine the path of movement to account forthe adjustment to the one or more of the determined plurality ofpositions of the first sensor.